classification study based on RNA. Divided prokaryotes into two groups; bacteria and archaea because they are different (bacteria have different cell membrane structure, different enzymes)

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What is continuous variation?

two extremes and range of intermediates, most individuals are close to the mean value e.g. height, length of leaves

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What is discontinuous variation?

Two or more distinct categories with no intermediate values e.g. sex, blood groups

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What is natural selection?

the selection by the environment of particular individuals that show certain variations. These individuals will survive to reproduce and pass on their variations to the next generation

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What is speciation?

geographical separation (allopatric speciation) or reproductive barrier (sympatric speciation) dues to biochemical change preventing fertilisation. These prevent effective breeding between members of a species